Thread-cutting mechanism.



H. W. OSTER. THREAD CUTTING MEGHAN/ISM. APPLICATION FILED APB.1B,;1908.

Patented Dec. 6, 1910.

4 BHEETS BHEET I.

@061: 1'01. M W M 7% \MM H. ,W. OSTER. THREAD OUTTING MECHANISM.APPLIOATION FILED APR. 18, 1908.

Patented Dec. 6, 1910. 4 sums-91mm 2.

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THREAD CUTTING MECHANISM.

APPLICATION FILED APRJB, 190B.

. Patented D60. 6, 1910.

4 SHEETS-31113 3.

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H. W. OSTER.

THREAD CUTTING MECHANISM.

APPLIOATION FILED APR. 18, 1908.

Patented Dec. 6, 1910.

4 SHEETS-$111131 4.

' UNITED STATES PATENT OFFICE.

HERMAN w. os'rnn, or CLEVELAND, onro, assrcnon r0 THE os'rnnManurncrpamc commas, or CLEVELAND, OHIO, A conronarron or OHIO;

THREAD-CUTTIN G MECHANISM;

Specification of Letters Patent.

Patented Dec. 6, 1910.

Application filed April 18, 1908. Serial No. 427,819.

a citizen of the United Statw, residing at Cleveland, in the county ofCuyahoga and State of Ohio, have invented a certain new and usefulImprovement in Threaddjuttmg Mechanism, of which the following is afull, clear, and exact description.

It is the well nigh universal practice to employ chasers or dies forcutting threads on pipes and various other kinds of cylindrical stock.Such dies and chasers for the purpose are eiiicient, but they are notentirely satisfactory, because they are soon dulled and require frequentsharpening. I believe that some attempts have been made to use rotarycutters for cutting thread, but so far as I am aware such cutters haveonly been used in connection with mechanism where the stock to bethreaded is rotated in contact with the rotating cutters. This is notregarded as a seriously objectionable characteristic for certain kindsof work, but mechanism of this sort would not be satisfactory forthreading pipes or other long pieces of stock, principally because ofthe diiiiculty of controlling it and of handling it, and the size of themechanism required for so doing.

The present invention is a thread cutting mechanism employing rotarycutters which, obviously will not require as frequent sharp.- ening asdies or chasers, said cutters being mounted upon a rotary carrier whichis adapted to'be turned by suitable mechanism about the non-rotatingstock to be threaded, and to be moved lengthwise to give the properlead.

The invention, as shown, is embodied in the form of a portablehandoperated die stock; but it is not intended that the invention, asbroadly defined herein, shall be limlited to a die stock, or a portablehand too In the drawing, Figure 1 is an end view of a device embodyingthe invention, when portions of the end head plate are broken away toshow the interior mechanism. Fig. 2 is a transverse section view in theplane indicated by line Qr2 of Fig. 1. Fig. 3 is a sectional view in theplane indicated by line 33 on 1. Fig. 4 is a development of the trainofgears employed for driving the rotary cutters and ofv the means forsupporting said cutters and permitting said resents what may be calledsupport to move toward and from the axis of the stock, as hereinafterdescribed. Fig. 5 is. a sectional view in the plane indicated by line5-5 on Fig. 8.

Referring to the parts by letters, A repthechuck. His

a hollowcylindrical member through which I the stock to be threaded maybe passed, and in which said stock may be clamped in an axial position.B represents a tubular lead screw which is screwed into the chuck A.

1) represents the gear carrier which is in the form of a drum having atone end an inwardly turned flange d which is rotatably mounted upon thechuck A. A gear a is fixed to the chuck A within the drum D. A shaft Eis rotatably mounted in the drum D on an axis which is parallel with theaxis of the drum, but eccentric thereto. A pinion c secured to thisshaft meshes with the gear a. This shaft E is to be turned by suitablemeans applied to its projecting front end. A head plate C is fixed tothe front end of the tube 13, and fixed within the drum D. In theperiphery of this head plate G is a longitudinal groove 0 which extendsfrom one end to the other or the head plate. A block F having aninclined inner face f is fixed to the drum D and is slidably fitted inthe slot 0. lVhen, therefore, shaft E is turned and the chuck is fast tothe stock, drum D will, of necessity, rotate upon the chuck. Because ofthe engagement of the block F in the groove 0, the head plate C willrotate, and of necessity the leadtube B will rotate with it and willscrew into or out of the chuck. The lead ofthe screw threads on thesleeve B and chuck A is the same as that of the threads to be out uponthe stock.

A slide G is secured upon the head-plate C. It is held thereon in aradial guide-way c which permits it to move toward and from the axis ofthe device. This slide serves as the bearing for the shaft H which isparallel with'the axis of the device; and the cutters J are secured tothe outer end of this shaft. The slide G- engages at its outer end Withthe inner face of the block F, whereby the outward movement of the slideG is controlled. T

A train of gears is mounted in bearing brackets K, K, which are fixed tothe inner surface of the drum D. That is to say, there are three shaftsP, Q and R which are mounted in these brackets. To the shaft R 1 twogears 'r, 1" are fixed, the small gear bein inmesh with the gear 6secured to the shaft E. To the shaft Q, two gears g, g are secured,thelatter being in mesh with the gear 7. The gear 9 is in mesh with thegear p secured to shaft P; and another larger gear p secured to saidshaft is in mesh with an idler pinion t, which pinion is in upon theshaft P, and the other link of said toggle comprising the two members NN which loosely embrace the stud T and.also loosely embrace the shaft Hwhich may slide endwise therein. Because of the described toggle, theblock G is permitted to move radially toward and from the axis of thedevice without interrupting the connection of shaft H with its source ofrotary .motion above described. As has been before stated, the innerface of the block F with which the outer end of the slide G engages isinclined. That is to say, the farther removed any point of "said surfaceis from the left end of said block the greater is the distance of thatpoint from the axis of the device.

' The operation of the device is as follows: \Vhen the stock has beeninserted into the device and clamped in the chuck A, the shaft E isturned. The drum D is therefore caused to rotate. upon chuck A, butcannot move endwise thereon. The engagement of the block F in'the groove0 causes the head 40 plate C and the lead tube B to rotate. As the tubeB rotates, it screws into the chuck A at a rate corresponding with thelead of the screw thereon which, as stated, corresponds with the lead ofthe thread being cut by the cutters J. This movement of the tube Bcarries the cutters 'longitudi nally along the stock as they are movingaround the stock, and are at the same time. rapidly rotating upon theirown axis. During this movement of tube B, as it screws intochuck A, theslide G, by reason of its engagement with the inclined face of the blockF, is permitted to move radially outward and thereby the depthofthethread cut by the cutters is gradually decreased. In other words, thedevice, in the form shown, is adapted to cut a tapered thread upon thestock. During the outward or' inward movement of theslide G the togglereferred to will bend at its joint, but without interrupting operativeengagement of the gears constituting the train above described.

If it is not desired that the device shall'ri be adapted to cuttingtapered threads, the bearing of shaft H may be so constructed that ithas no-movement toward and from the axis of the device. In that event,it is not necessary that any of the gears constituting the train whichtransmits motion from the gear 6 to the gear 72. shall be supported by atoggle. In that event also, it is unnecessary that the inner face of theblock F shall be inclined, as stated. From this description, it will beunderstood the threads cut upon the stock may be tapered in any degreeor not at all by merely varying the inclination of the inner face of theblack F, or making it parallel with the axis of the stock, and makingthe outer end of the slide G suitably conform thereto.

.In order to withdraw the threaded stock from the device after thethread has been cut on the stock, one may remove block 'F and to do thathe has simply to loosen the cap screws 0 by whichthe block is clamped tothe drum D, andthen move said block endwise. This movement is permittedbecause the cap screws, 0 pass through a slot d? extending from the endof the drum inward. When the block F is removed then the operator may,by pulling outward on the projecting end of the shaft H move slide Gradially outward so as to entirely disengage the cutters J from thethreaded stock. The devices clamping the stock in the chuck may beloosened, and the stock withdrawn. The slide G may then be moved inwardand the block Freplaced and fastened, and then the shaft E maybe turnedin the reverse direction, whereby the sleeve B will be turned in thereverse direction and unscrewed from the chuck A.

Havin described my invention, I claim:

1. In t read cutting mechanism, the combination of a tubular chuckadapted to be clamped upon the stock to be threaded, a J concentric,tube rotatable relatively to said chuck and having a lead-screwconnection therewith and having also a substantially radial guide-way, abearin block supported by said tube in sai guide-way and movable thereintoward and from its axis, means controlling the outward movement of saidblock, a cutter shaft rotatable in said block, and means for turningsaid tube slowly and the cutter shaft rapidly.

2. In thread cutting mechanism, the combut incapable of endwise movementrelative.

thereto, a train of gears mounted upon said drum and adapted to transmitmotion to:

said cutter, and means compelling the tube and drum torotate in" unison.

3. In thread cutting mechanism, bination of a tubular chuck adapted tothe com-- ward and from its axis, a cutter shaft r0ta-' tably supportedin said block, means controlling the outward movement of said block, adrum rotatable about the chuck but incapable of endwise movementrelative thereto, a train of gears mounted upon said drum a toggle whoselinks are respectively pivoted upon an axis coincident with the axis ofthe last gear of-sai d train and with the axis of the cutter shaft, anidler gear mounted on the pivot of said toggle in mesh with the lastgearof said train, and a gear in mesh with said idler gear having a tongueand groove connection with the cutter shaft.

4. In thread cutting mechanism, the combination of a tubular chuckadapted to be clamped upon the stock to be threaded, a concentric tuberotatable relatively to said chuck and having a lead screw connectiontherewith, a bearing block supported by said tube and movable toward andfrom its axis, a cutter shaft rota table in said block, a drum rotatableupon said chuck but incapable of endwise movement relative thereto,means compelling said drum and tube to rotate in unison, and an inclinedsurface carried by said drum with which the outer end of said bearingblock engages, and mechanism for rotating said cutter shaft rapidly andsaid drum slowly,

5. In thread cutting mechanism, the combination of a tubular chuckadapted to be clamped upon the stock to be threaded, a concentric tuberotatable relatively to said chuck and havin a lead screw connectiontherewith, a hea plate fixed to said tube having a longitudinal groovein its periphery, a bearing block mounted in guideways on said headplate, a drum rotatable upon said chuck but incapable of movement'relative thereto, a block fixed to said drum and projecting into theslot of the head plate and engaging on its inner face with the outer endof said bearing block, a cutter shaftrotatable in said bearing block,and means for turning the drum and cutter shaft.

6. In thread cutting mechanism, the combination of a tubular chuckadapted to be clamped upon the stock to be threaded, a

concentric tube rotatable relatively to saidchuck and having a leadscrewconnection therewith, a cutter rotatably supported upon said tube, adrum rotatable about the chuck but incapable of endwise movementrelative thereto, a train of gears mounted upon said drum and ada ted totransmit motion to said cutter, ant? and drum to rotate in unison, ashaft rotatably mounted in said drum on anaxis parallel with the axis ofthe drum, a gear secured to said shaft, and a gear fixed to said chuckinmesh therewith, and a train of mechanism transmitting motion from saidshaft tothe rotatable cutter.

7. In a thread cutting mechanism, the

means compelling the tube combination of a tubular chuck adaptedto beclamped on the stock to be threaded, a concentric tube rotatablevrelatively to said chuck and having a lead screw connection therewith,a shaft bearing supported by said tube and movable thereon toward andfrom the axis of said tube, a shaft mounted in said bearing, a cuttersecured to said shaft, means for turning said tube. and shaftsimultaneously about their respective axes, a pat tern plate controllingthe movement of said shaft bearing away from the axis of the tube, and amember to which said pattern plate is fixed,-which member is rotatableon the chuck but has no longitudinal movement relative thereto. 1

8. In a thread cutting machine, the combination of a tubular chuckadapted to be clamped on to the stock to be threaded, a concentric tuberotatable relative to said chuck, means for moving said tube longitudinally relative to the chuck as the tube is turned, a shaft bearingsupported by said tube and movable thereon toward and from the axis ofthe tube, a shaft mounted .1n said bearlng, a cutter secured tosaid'shaft, means for turning said tube and shaft'simultaneously abouttheir respective axes, a pattern plate controlling the movement of saidshaft bearing away from the axis of the tube, and a member to which saidpatternv plate is fixed,which member is rotatable on the chuck but hasno longitudinal movement relative thereto.

In testimony whereof, Ihereunto affix my signature in the presence oftwo witnesses.

HERMAN w; OSZIER.

Witnesses:

E. L. THURSTON, R. B. TEwxsBUnY.

